Perricone MD Cold Plasma Plus+ Sub-D/Neck (£119) is the latest product in the brand's classic Cold Plasma range. Targeting saggy, thin skin along the jawline, neckline, and décolleté, this formula is a concentrated version of the brand's original Cold Plasma cream. In addition to the brand's proprietary ingredient, DMAE (which has both anti-inflammatory and skin-smoothing properties), this formula also includes copper peptides (to strengthen damaged skin), encapsulated caffeine (which jolts the skin cells on the surface into action), niacinimide, hyaluronic acid, and omega fatty acids, all of which help promote firmer, smoother, tighter skin.